The typical connection below shows that the overheating protection with a small component count and a minimal temperature variation is realized and a single diode enables to combine a latch circuit with a overvoltage protection circuit. This circuit allows to adjust a latch temperature easily by adjusting a detection resistor. Note: In the case of dead short, the overheating protection is not available because there is no voltage appearing on the secondary-side. In this case, please protect the unit by the primary side detection as usual.